Surgical procedures involving the knee joint are more difficult than many other surgical procedures because of the very small spaces in which to work inside the knee joint itself. Within the last few years the arthroscope, a small telescope designed to be inserted into the knee joint, has been developed to allow visualization within these small spaces. Initially, arthroscopes were used merely for diagnostic purposes. More recently, however, arthroscopes have been employed during the surgical procedure itself to permit improved visualization within the knee joint. It is even practical and beneficial to use more than one arthroscope during some surgical procedures on the knee joint. These arthroscopes may have different lenses and be positioned at different angles with respect to the knee joint as a further aid to the surgeon during the operation.
Obtaining the proper exposure of the knee joint during surgery is necessary for a successful result. Exposure required the opening up of the knee joint by the application of forces and moments which may even distort the joint thereby making the spaces within which the surgeon must work a bit larger. When surgery is performed under arthroscopic visualization, good exposure is essential not only to give the surgeon more room to perform the procedure but also to provide better visualization of the surgical field.
Heretofore, the opening up of the knee joint to provide the desired exposure was accomplished by an assistant who moved the knee through its various ranges of motion while applying considerable force to the knee joint. Stamina is required of such an assistant because knee operations often last for an hour or more; and strength is necessary because of the relative inelasticity of the ligaments supporting the knee joint. An inexperienced assistant, moreover, could actually make matters worse by not holding the knee joint steady enough to allow the surgeon to work expeditiously. When surgery was performed arthroscopically, the assistant supported the knee so as to open up the joint, and the surgeon held the arthroscope with one hand while performing the shaving, cutting or other procedure with his or her other hand.
At a later stage of development, the arthroscope was connected to a television camera so that the surgeon could view a monitor rather than looking through the device directly. In this situation, a second assistant was required to hold the arthroscope/camera combination and to move it according to the surgeon's instructions. Not only does the connection of arthroscopes to television cameras entail the cost of a second surgical assistant, but also, the television equipment itself is very expensive, so that only large medical centers can invest in such a system. Even with the use of a television system, the problem of maintaining the knee in the optimum position to provide good exposure remained unsolved.
It is, therefore, an object of the present invention to provide apparatus which not only applies and maintains forces and moments to the knee joint to provide the desired exposure, but which also is adapted to support one or more arthroscopes or other surgical implements in a preselectable and adjustable relation to the knee joint during surgery.
A further object of the invention is to provide such apparatus which is simple of construction and yet highly effective to provide the necessary exposure within which the surgeon can perform as compared with the capability of a human assistant.
Yet another object of this invention is apparatus which can apply and maintain forces and moments to the knee joint through all eight of its ranges of motion.